The purpose of this study is to investigate by pretested questionnaires whether dietary and/or lifestyle habits of American black males are related to the high incidence of prostatic carcinoma. Associations between prostate cancer and the following epidemiologic variables were detected: 1. past history of chronic urethritis, prostatitis or cystitis (p less then 0.01); 2. exposure to pre-antibiotic treatment (transurethral irrigation) for chronic urethritis, prostatitis or cystitis (p less than 0.05); 3. family history of cancer (p less than 0.05); 4. occurrence of periods of impotence of one month or longer (p less than 0.05); 5. use of androgens and central nervous system stimulants (p less than 0.01); 6. use of antihypertension medications and other cardiac drugs (p less than 0.05); 7. use of antidepressant medications after age 50 (p less than 0.05). In the nutritional part of our study the following observations were made: there was a significant association between consumption of citrus fruits and prostate cancer (p less than 0.05). More controls than patients consumed other fruits (not citrus) (p less than 0.006). This fruit group is a good source of vitamin A. Our data suggests that the amount (dose) of vitamin A from other fruits is important in the prevention of prostate cancer. More patients consumed starchy foods as compared to controls (p less than 0.045); patients used more margarine regularly in cooking than controls (p less than 0.04). Patients drank wine less often than controls (p less than 0.011). This finding suggests that wine may have some protective effect against prostate cancer.